Examples of use
In major keys, Minor 7th chords works well on the II,III, and VI (2nd,3rd and 6th) degrees of the scale. It can be used as a way of adding an extra color to a standard minor chord.
In Db major, the Ebm7 is the chord on II and can form part of a II7-V-I pattern.

In B major, the Ebm7 is the chord on the III (3rd) degree of the scale. This progression starts with the tonic B and moves to Ebm7 before moving down to another minor 7th chord, Dbm7, forming a progression I-III7-II7.